import axios from 'axios' // 引入axios
import { MessageBox, Message } from 'element-ui' // 消息提示框 顶部消息提示
import store from '@/store' // vuex的store对象
import { getToken } from '@/utils/auth' // 获取token方法

// create an axios instance
// 创建axios实例（service里面带前缀基地址和超时时间）
const service = axios.create({
  // 知识点：nodejs+webpack下的环境变量
  // process.env ->node.js环境下的内置全局变量（任意处使用）
  // 效果：获取敲击命令，执行时的环境变量
  // yarn dev（开发环境启动）->process.env上会被nodejs+webpack挂载.env.development
  // 文件里的变量值到这里
  // yarn build:prod(打包准备放入生产环境)->process.env上会被挂载.env.production文件里的变量值到这里
  // 作用：根据敲击的命令自动加载对应不同的环境变量，开发时是一个基地址，上线时是一个基地址

  baseURL: process.env.VUE_APP_BASE_API, // url = base url + request url
  // withCredentials: true, // send cookies when cross-domain requests
  timeout: 5000 // request timeout
})

// request interceptor
// 请求拦截器
service.interceptors.request.use(
  config => {
    // do something before request is sent

    if (store.getters.token) {
      // let each request carry token
      // ['X-Token'] is a custom headers key
      // please modify it according to the actual situation
      config.headers['X-Token'] = getToken()
    }
    return config
  },
  error => {
    // do something with request error
    console.log(error) // for debug
    return Promise.reject(error)
  }
)

// response interceptor
// 响应拦截器
service.interceptors.response.use(
  /**
   * If you want to get http information such as headers or status
   * Please return  response => response
  */

  /**
   * Determine the request status by custom code
   * Here is just an example
   * You can also judge the status by HTTP Status Code
   */
  response => {
    const res = response.data

    // if the custom code is not 20000, it is judged as an error.
    if (res.code !== 20000) {
      Message({
        message: res.message || 'Error',
        type: 'error',
        duration: 5 * 1000
      })

      // 50008: Illegal token; 50012: Other clients logged in; 50014: Token expired;
      if (res.code === 50008 || res.code === 50012 || res.code === 50014) {
        // to re-login
        MessageBox.confirm('You have been logged out, you can cancel to stay on this page, or log in again', 'Confirm logout', {
          confirmButtonText: 'Re-Login',
          cancelButtonText: 'Cancel',
          type: 'warning'
        }).then(() => {
          store.dispatch('user/resetToken').then(() => {
            location.reload()
          })
        })
      }
      return Promise.reject(new Error(res.message || 'Error'))
    } else {
      return res
    }
  },
  error => {
    console.log('err' + error) // for debug
    Message({
      message: error.message,
      type: 'error',
      duration: 5 * 1000
    })
    return Promise.reject(error)
  }
)

export default service // 导出axios service对象
